1 files changed, 59 insertions, 0 deletions
diff --git a/src/test/test_rng.c b/src/test/test_rng.c
new file mode 100644
index 0000000000..ebaffb74f5
--- /dev/null
+++ b/src/test/test_rng.c
@@ -0,0 +1,59 @@
+/* Copyright (c) 2016-2020, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/*
+ * Example usage:
+ *
+ * ./src/test/test-rng --emit | dieharder -g 200 -a
+ *
+ * Remember, dieharder can tell you that your RNG is completely broken, but if
+ * your RNG is not _completely_ broken, dieharder cannot tell you whether your
+ * RNG is actually secure.
+ */
+
+#include "orconfig.h"
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include "lib/crypt_ops/crypto_rand.h"
+
+int
+main(int argc, char **argv)
+{
+  uint8_t buf[0x123];
+
+  if (argc != 2 || strcmp(argv[1], "--emit")) {
+    fprintf(stderr, "If you want me to fill stdout with a bunch of random "
+            "bytes, you need to say --emit.\n");
+    return 1;
+  }
+
+  if (crypto_seed_rng() < 0) {
+    fprintf(stderr, "Can't seed RNG.\n");
+    return 1;
+  }
+
+#if 0
+  while (1) {
+    crypto_rand(buf, sizeof(buf));
+    if (write(1 /*stdout*/, buf, sizeof(buf)) != sizeof(buf)) {
+      fprintf(stderr, "write() failed: %s\n", strerror(errno));
+      return 1;
+    }
+  }
+#endif /* 0 */
+
+  crypto_fast_rng_t *rng = crypto_fast_rng_new();
+  while (1) {
+    crypto_fast_rng_getbytes(rng, buf, sizeof(buf));
+    if (write(1 /*stdout*/, buf, sizeof(buf)) != sizeof(buf)) {
+      fprintf(stderr, "write() failed: %s\n", strerror(errno));
+      return 1;
+    }
+  }
+}